Carbon nanostructures have distinct electrical, thermal and mechanical properties that are desirable for use in structural applications as well as in electrically and thermally conducting functional materials. Carbon nanostructures have been combined with matrix or other materials to provide carbon nanostructure-reinforced composite materials having enhanced properties relative to the corresponding non-composite materials. Carbon nanostructure-reinforced composite materials are being used as, amongst other things, lightweight, rigid and high-strength materials. There is a need in the art for improved methods for preparing carbon nanostructure-reinforced composite materials having these superior properties.